Method of electric welding wires



July 23, 1929 w. D. BuMsjrEAp ET AL 1,722,195

lmao op ELECTRIC' WELDING nnss Filed April 2;, 1928 q \HIIMIIILILIMIIII r Patented July i 23, 1929.

UNITED STATES PATENT OFFICE.

WILLIAM D. BUMSTEAD, OF CLEVELAND, AND EDWARD A'. AURADA, OF CLEVELAND HEIGHTS, OHIO, ASSIGNORS TO GENERAL OF NEW YORK.-

-ELECTRIC COMPANY, A CORPORATION METHOD OF ELECTRIC WELDING WIRES.

Application led April 23, 1928. Serial No. 272,181.

Our invention relates to methods and apparatus for welding wires together and more especially for producing leading-in conductors'for electric incandescent lamps and similar devices which comprise a comparatively short length of wire having a. co-eflicient of expansion approximately the same as glass, said wire being welded to another wire which is composed of copper, nickel or other higher expansionwire. It has been customary to weld these wires by the so-called percussive welding method which is disclosed in patent to Chubb No. 1,066,468 of July 8, 1913. Ac-

cording to that method, the two wires whichl are to be welded together are each gripped in such a way as to make electrical contact between each of the sections of wire and its gripping device which is connected to the high potential electrical discharge circuit. It is desirable to use wire coated with a borate for the sealing-in portion, and in such case it is necessary for the gripping device to penetrate the coating in order to make the proper electrical contact. This not only chips o part of the coating but also causes an accumulation of the borate powder around the contacts, and in view of the fact that it is necessary to produce great numbers of these wires, this becomes more or less of a nuisance. Ac- 3o cording to our invention this is obviated by making electrical contact with the ends of the wires. It will be obvious that our invention also has advantages when used for uniting uncoated wires since the necessity for tight gripping of the wires is removed and the operation is performed with less chance ofdistortion of the wire. Various other features and advantages of our invent-ion will appear from the description which follows of a species thereof.

An instance of the application of our invention is the production of leading-in wire comprising a sealing-in portion consisting of so-c-alled Dumet wire. lThis is disclosed in Fink Patent No. 1,498,908, June 24, 1924, and

this is usually coated with a borate as dis-l closed in Van Keuren Patent No. 1,427,870, September 5, 1922.

In the drawing, Fig. 1 is a sectional elevation of an apparatus constituting an embodiment of our invent-ion; Figs. 2, 3 and 4 are diagrammatic illustrations'of steps in our process; Fig. 5 shows the completed wire; and Fig. 6 shows a section of the sealing-in portion of the wire on an enlarged scale.

Referring now to the drawing and more particularly to Fig. 1 which illustrates a portion of a Welding machine comprising ourinvention, this machine comprises a base 10 which supports the various mechanisms which feed, trim and position the wires preparatory to welding them together. We are aware that this combination of mechanisms is not new in the art and have therefore purposely omitted some of them in the drawing for the sake of clearness. As shown, an arm 1l comprising jaws 12 adapted to receive and gri p a short length of wire 13 is actuated so as to transfer the said wire from its source of supply (not shown) to a position where one end thereof may be conveniently engaged by an aligned contact member 14 which is advanced toward it. The movement of the contact member 14 is accomplished by a cam 15 which actuates a rod 16 through roller 1,7 carried on the end of said rod. The movement of the rod 16 is communicated to another rod 18 through the intermediate compression spring 19. The rods 16, 18 and spring 19 are slidably mounted in bea-ring 20 formed in the standard 21 extending from the base 10 of the machine. Attached to the outer end of the rod 18 is the contact member 14 preferably of tungsten or other refractory metal. The shape of the cam 15 is such that when its high point bears against the roller 17 the rods will be moved forward to a position where the contact member 14 may touch one end of the wire 13. The spring 19 at this time is compressed suiiiciently to hold the contact 14 firmly against the end of the wire.

Another wire 22 which is to be welded to the opposite end of the wire 13 is placed in a chuck 23 inaccurate alignment with the wire 13. The'chuck 23 is carried in a collar 24 forming part of a bracket 25, said bracket being slidably mounted on horizontal rods 26 extending from the standard 27. At the proper time the bracket 25 is moved forward in order that the end of the wire 22 'may contact with the end of the wire 13. At the instant the ends of these wires contact a condenser located in the electrical circuit is disof contact i's sufficiently great to produce a Weld between the wires. i

After the completion of the weld the roller 17 passes over the high point on cam 15 allowing the compression spring 19 to push the rod 16 backwardly. During this time the rod 18 is returned to its initial position by springs 28 which pull vit backwardly thereby disengaging the contact'll from the end of the wire 13. Thejaws and likewise the chuck 23 are next opened to allow the revmoval of the completed weld.

Electrical energy is supplied from a suitable source, such as a generator (not shown), to a condenser 30. From one terminal of the condenser the current is directed to the contact member 14 through conductor 31. The other terminal of the condenser is connected to the chuck 24 through conductor switch 33 and conductor 34 making the chuck one terminal of the welding machine, the other terminal being the vcontact member 14. When l the switch 33 engages the contact 35 the condenser is charged and the welding circuit is open. Just prior to the welding operation the switch 33Ais caused to engage the contact 36 in order that the condenser will discharge the instant the ends of the wire 13 and 22 meet thereby welding them together.

What we claim as new and desire t'osecure by Letters Patent of the United States, is-

1. The method of uniting two wires which consists in forming an electrical contact between the end of one of said Wires and a high potential electrical discharge circuit and then engaging the other end of said Wire with an end of the other wire and completing the high potential discharge circuit.

2. The method of uniting a Wire having an insulating coating with another wire which consists in forming a contact between one uncoated end of said first wire and a high potential electrical dischargecircuit and then engaging the other uncoated end of said wire with an end of the other wire and completing the high potential discharge circuit.

In witness whereof, we have hereunto set our hands this 20th day of April', 1928.

VILLIAM D. BUMSTEAD.' EDWARD A. AURADA. 

